1. Field of the Invention
The present invention relates to an injection molding machine, and more particularly to setting and change of molding conditions.
2. Description of Related Art
In molding products by means of an injection molding machine, various molding conditions must be set individually for processes of molding operation, including injection, filling, pressure holding, metering, mold opening, mold closing, and mold clamping. These molding conditions to be set are large in number. In order to obtain conforming molded products, moreover, condition setting operation is required such that test injection is repeated as molded products obtained by the test injection are observed and that molding conditions are changed. Since this condition setting operation is hard and time-consuming, some conventional systems have been tried as follows (see JP59-158237A, JP60-196324A and JP61-248722A). First, a set of values of all the molding conditions with which conforming molded products are obtained are stored in advance corresponding to a mold for use or the molded products in a storage device of the injection molding machine or a storage device or storage medium outside the machine. When this mold is then used to mold identical products, the set values of the molding conditions stored corresponding to the mold or the molded products are read from the storage device. The read set values of the molding conditions are automatically collectively set in the injection molding machine.
In general, the sets of molding conditions that are stored in the storage device or the external storage medium are stored according to the mold or the molded products. In some cases, sets of molding conditions of a plurality of types may be prepared for the same mold and stored in advance. Also in these cases, any of the sets of molding conditions corresponding to the mold is selected and set automatically. Thus, the molding conditions are generally changed and automatically set as the mold is replaced with a new one.
However, set items of molding conditions that are set in the injection molding machine include attended and unattended operation modes, heater disconnection detection values, confirmation of load cell pressure correction, etc., which are not associated with the mold replacement, that is, set items of molding conditions that should not be changed despite the change of the mold. Further, the set items include a machine state to be indicated by an alarm lamp, a timer based on a calendar function, etc., which are settled depending on other conditions regardless of the mold. Set values for these set items should not be changed even when they are set after the molding conditions are read from the storage device in association with the mold replacement. These set items of the injection molding machine include ones whose set values are changed when the molding conditions are read from the storage device and ones whose set items are not.
There is known an invention (see JP 2006-95760A) as an example of a system for clarifying this discrimination. According to this invention, molding conditions that depend on the mold and other molding conditions are stored separately. A mold ID is attached to the molding conditions based on the mold and previously stored corresponding to the mold. In replacing the mold with a new one, molding conditions that depend on the mold to be used are read and set collectively. In displaying the molding conditions, it is discriminated whether or not they are settled depending on the mold.
Also known is an invention (see JP 2001-322150A) in which molding conditions are previously set in an injection molding machine. In reading and changing molding conditions stored in an external or internal memory, all the molding conditions including temperature data in the memory are read and substituted for the previously set molding conditions. Alternatively, only those other data than the temperature data, out of the molding conditions stored in the external or internal memory, are read and substituted for the previously stored molding conditions.
When the molding conditions are read and set collectively, whether or not a set value for a set item of a certain molding condition changes in association with the molding condition reading operation generally depends on the design of the manufacturer of the injection molding machine. In some cases, however, the set values for the items having so far been set in the injection molding machine may be expected to be used without being changed even though they are designed to change when the molding conditions are read from the storage device. In order to fix the machine operation after a shutdown sequence or a monitor item for conformity determination, for example, the set values for the set items sometimes should not be changed when the molding conditions for the substituted mold are read and set.
If molding conditions that are set as master conditions for the confirmation of molding stability when molds are completed in a mold manufacturing department are transferred together with the molds to a mass-production plant, moreover, the administration of the plant sometimes may want to fix set items of some molding conditions without change. If the master conditions are directly set without modification, in this case, there arises a problem that the set values for the set items for all the molding conditions are changed into the master conditions.
Therefore, it is desirable that items of the molding conditions, of which value should be fixed when collectively setting the read values of the molding conditions, is made selectable.
On the other hand, if the molding condition items of which values should be fixed is made selectable, there arises a problem in collectively setting molding conditions read from the storage device, which have set values of such molding conditions items to be changed. The problem arises because there are some molding conditions correlated with other molding conditions. If items of such some molding conditions are selected to be the items of which values are fixed, the set values of the correlated molding conditions are contradicted with each other because the some correlated molding conditions are unchanged when the other molding conditions are changed. Thus, there arises a case where optimal values of the molding conditions are not set.
As an example of the above mentioned correlated molding conditions, there are an ejection start position (an position of a movable mold at which an ejecting of an product is started) and a mold opening completion position. The ejection start position should be set between a mold opening start position (mold closed position) and the mold opening completion position of the movable mold. If the item of the ejection start position is selected to be the item of which values should be fixed, there arises a contradictory case where the ejection start position is not set between the mold opening start position and the mold opening completion position when a predetermined set of molding conditions having a value of the mold opening completion position smaller than the fixed set value of the ejection start position are read from a storage device and collectively set to the set values of the molding conditions of the items (including the mold opening completion position) other than the items of which value should be fixed.
Further, in the case where both of a function #1 and a function #2 can not be enabled, if the function #1 is selected to be fixedly enabled, there arises a problem that the function #2 is also made enabled when a predetermined set of molding conditions having a value “enable” of the function #2 are read and collectively set to the set values of the molding conditions.